Fast and Furious: Eric Holder cleared but 14 faulted
The US justice department has cited 14 people for possible disciplinary action for their roles in a botched gun-running operation.
Operation Fast and Furious saw US agents lose track of hundreds of illegal guns sold in Arizona and allowed into Mexico to target dealers.
The inspector general's 471-page report comes after a 19-month review.
Attorney General Eric Holder was not criticised, as no evidence was found he knew about the controversial tactics.
Mr Holder was held in contempt of Congress in June for not handing over documents related to the operation.
Two of the illegal weapons were found in December 2010 at the scene of a US border agent's murder. Fast and Furious ended in early 2011.
No criminal charges were recommended as a result of the report.
The most senior official cited by Inspector General Michael Horowitz's report was Lanny Breuer, head of the justice department's criminal division.
Mr Breuer was criticised for not alerting his superiors in 2010 to flaws in a similar programme, known as Operation Wide Receiver, which started under former President George W Bush.
A "series of misguided strategies, tactics, [and] errors in judgment" all contributed to the failure of Fast And Furious and Wide Receiver, the report said.
The problems dated back to 2006 but current senior officials were criticised for failing to question the tactics used during Fast and Furious.
The strategy known as "gun-walking", allowing suspected straw purchasers to leave gun stores with weapons with the intent of tracking them, was barred under a long-standing departmental policy.
The inspector general also concluded that poor internal information-gathering and communication at the justice department and the Bureau of Alcohol, Tobacco and Firearms (ATF) caused them to misinform Congress about the operation.
"The key conclusions are consistent with what I, and other justice department officials, have said for many months now," Mr Holder said in a statement.
Two other top justice officials named in the report, Kenneth Melson, the former head of ATF, will retire after its publication. Jason Weinstein, a senior criminal division official, will resign.
Mr Holder said officials cited in the report, from the ATF as well as the US Attorney's Office for the District of Arizona, have been referred for disciplinary action.
In June Mr Holder became the first sitting attorney general to be held in contempt of Congress. He faced proceedings after the House Oversight Committee led its own investigation into the operation.
The roots of that investigation began on 4 February 2011 when the justice department sent lawmakers a letter denying it had sanctioned or otherwise knew about guns illegally ending up in Mexico.
The department withdrew the letter 10 months later, acknowledging the operation had allowed guns across the border.
Led by Republican Darrell Issa, the House Oversight Committee subpoenaed documents for that 10-month period.
The justice department sent the committee more than 7,000 documents relating to Fast and Furious, and to a similar operation that took place during the George W Bush administration.
The Department of Justice said it had denied access to the rest of the files because they contained information that could affect ongoing criminal investigations.
The White House then raised the stakes by announcing it would exert executive privilege to protect the documents in question from subpoena.
Dan Pfeiffer, an Obama administration communications director, called the vote a "transparently political stunt".